Grass Apes

Molly Webster opens by describing an invitation to tell a story about the park space where she would perform: a shady glade with a lawn, trees, and rocks. She initially considered mushrooms or New York City squirrels, but a horticulturist kept talking about grass and how landscapers use it almost like an instrument that makes sound. Molly was skeptical—“what could be interesting about grass?”—so producers Anissa Vita and Joe Strogatz asked people in New York parks what they thought about it. The answers ranged from rolling around, mowing lawns, daughters, girlhood, horses, grass stains, cats, and the other meaning of “grass,” to its smell and its unpleasantness underfoot. The responses suggested that grass is everywhere but usually overlooked. Molly compares it to a green screen: a background that is erased so more important foreground subjects stand out. Biologist and writer David George Haskell argues that ignoring grass means missing not only the plant’s story but one of the central stories of human history. He calls grasses our “co-creators,” because their transformation of the planet helped make the appearance of humans possible.

Haskell takes the story back roughly 30 million years, when the ancestors of apes lived mainly in forests and ate insects and fruit. As the planet cooled, polar ice expanded, and many regions became drier, small patches of grass began appearing in forests. Over the following 10 to 20 million years, grasslands expanded on different timescales across different continents, changing Earth from a mostly wooded planet into one containing extensive grasslands. Molly asks whether grasses simply overpowered trees. Haskell says grasses instead exploited environmental changes, including falling atmospheric carbon dioxide; they are efficient at taking in carbon dioxide and converting it into sugars. They also thrive in seasonally dry climates and evolved to survive fire. Their growing tissue stays low to or below the ground, so a fire burns the disposable leaves while leaving the tissues that can produce new stems, roots, and leaves intact. Grass therefore sprouts back after the fire. Mammals such as horses and hippopotamuses moved into these expanding grasslands, but grass was difficult to eat: its blades are tough and contain silicate, a glass-like material that helps resist wind and overenthusiastic grazing. Haskell also explains that animals may use grass to purge their guts or bind and expel worms, which gives Molly a vivid explanation for why dogs sometimes eat it and vomit.

Although human ancestors may have found grass leaves unpleasant and difficult to digest, Haskell says they discovered another way to eat the plant: its seeds. A grass seed contains a plant embryo surrounded by a large food store, mostly starch and protein with some oils. In grasses, that store can make up about 80% of the seed’s interior, giving the new plant a substantial “lunchbox” for its first days and weeks of growth. Humans recognized these concentrated packets of nutrition and began incorporating them into their diet. Haskell says oats, wheat, rice, corn, millet, barley, sorghum, and sugarcane are all grasses. Wheat makes bagels, rice is a grass, corn is maize, and even high-fructose corn syrup comes from one. He estimates that wheat, corn, and rice together account for about 60% of all the calories humans eat worldwide. The beef, lamb, and chicken people eat are also connected to grasses because those animals either graze or are fed corn, oats, and other largely grass-based foods. Over at least the last 10,000 years, humans selected grasses for fatter kernels and seeds that stayed attached to the stem instead of falling away. Molly and Haskell turn this into the image of “grass motherhood”: when people eat pasta, tamales, rice, or other foods, grasses are effectively nurturing them. In that sense, humans are “grass fed” too.

Haskell argues that grasslands may have helped shape the human body as well as the human diet. In a forest, an ape can use its forelimbs to move through branches; in an open grassland, there are fewer branches, freeing the forelimbs for manipulating objects. Walking on two legs is also more energy-efficient than walking on four through open space. He presents this as one possible reason bipedalism evolved, while acknowledging that many factors contributed and that the old idea that humans stood up mainly to see over tall grass is only part of the story. Molly adds that human feet contain many receptors sensitive enough to detect the topography of grass, potentially even a single blade. Physical therapists sometimes prescribe barefoot walking on grass for mobility issues. Haskell suggests that this sensitivity is a remnant of a long relationship with grassland environments, prompting Molly to joke that she needs to reclaim her “grass ape ancestry” after wearing shoes so much. They play with a hypothetical scientific name, “Homo poacea”—from Poaceae, the grass family—and connect the idea to Gen Z’s “touch grass” phrase. Haskell says that if humans were named for their main food source and habitat, they would be grass apes rather than jungle apes.

Haskell says grass is still embedded in people physically and perceptually. When someone lies in a park, grass absorbs high-frequency sounds and scatters other sound waves because its blades point in different directions. The result is a softer soundscape: airplanes, horns, and city noise become less harsh when the listener puts their head close to the ground. Molly realizes that lying in grass can feel calming not only because someone is resting away from buildings, but because grass is literally dampening the surrounding sound. Grass also releases aromas, especially when it is rubbed, and some of those compounds interact with nerve cells or may enter the bloodstream. After rain, soil microbes and fungi working with grass roots contribute additional smells. Haskell says these smells resemble the signals of a healthy habitat that surrounded human ancestors for hundreds of thousands, perhaps millions, of years. The episode ends with Molly sitting barefoot in grass on the last day of summer, noticing the warmth, the softened world, and eventually ants crawling on her back. The episode grew from a live Little Island performance called “Grass Fed,” featuring Haskell, Foley artist Steven Wendt, and dance company Pilobolus.